JP2019052766A - Shovel and directional control valve group for construction machine - Google Patents

Abstract

To provide a directional control valve group for construction machine capable of appropriately controlling a supply amount of pressure oil discharged from a hydraulic pump to a hydraulic cylinder.SOLUTION: A directional control valve group for construction machine for controlling a supply amount of pressure oil discharged from a hydraulic pump to a hydraulic actuator, comprises: a cylinder port Cprt configured to supply oil pressure to the hydraulic actuator; a bridge passage Rb connected to the cylinder port Cprt in such as manner as to switch communication/interruption according to change of a position of a spool; and an internal passage RV1 configured to supply oil pressure discharged from the hydraulic pump to the bridge passage Rb, wherein the spool is arranged in the internal passage RV1.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a directional control valve group for construction machinery.

  Some construction machines perform control (bleed-off control) for returning a part (for example, surplus) of pressure oil discharged from a hydraulic pump to a hydraulic oil tank. In order to perform bleed-off control, some construction machines include a clearance (for example, a bleed opening Sbo in FIG. 7) for returning pressure oil in the spool of the direction control valve. The construction machine performs bleed-off control by changing the opening area of the bleed opening (for example, Patent Document 1).

JP-A-11-257302

  Since the amount of pressure oil (hydraulic oil) supplied to the hydraulic actuator varies depending on the work purpose, in a construction machine equipped with a plurality of hydraulic pumps, by joining the pressure oil discharged from the hydraulic pump using a merging circuit, There is one that secures the amount of pressure oil supplied to the hydraulic actuator.

  However, when a junction circuit is added to the technique disclosed in Patent Document 1, for example, as shown in FIG. 6, a cut valve Vct and an output port Pout are provided to allow pressure oil to flow out, and an input port Pin is further provided. Therefore, it is necessary to flow in (join) the pressure oil. For this reason, the passage of the hydraulic circuit (for example, an external passage communicating the output port Pout and the input port Pin) becomes complicated, and the pressure loss of the pressure oil may increase. In addition, when a junction circuit is added to the technique disclosed in Patent Document 1, another set of cut valve Vct, output port Pout, and the like are provided in order to allow pressure oil to merge in both directions. There was a need. That is, when a junction circuit is added to the technique disclosed in Patent Document 1, the hydraulic circuit of the construction machine may be enlarged due to the cut valve Vct and the output port Pout.

  The present invention has been made under such circumstances, and provides a directional control valve group for construction machines that can more appropriately control the supply amount of hydraulic oil discharged from a hydraulic pump to a hydraulic cylinder. Let it be an issue.

  A directional control valve group for a construction machine according to an embodiment of the present invention is a directional control valve group for a construction machine that controls a supply amount of pressure oil discharged from a hydraulic pump to a hydraulic actuator. A cylinder port that supplies pressure oil, a bridge passage that is connected / disconnected by a change in position of the cylinder port and the spool, and an internal passage that supplies pressure oil discharged from the hydraulic pump to the bridge passage The spool is disposed in the internal passage.

  According to the directional control valve group for a construction machine according to the embodiment of the present invention, the supply amount of the pressure oil discharged from the hydraulic pump to the hydraulic cylinder can be controlled more appropriately.

1 is a schematic external view illustrating an example of a construction machine according to an embodiment of the present invention. It is a hydraulic circuit diagram explaining an example of the hydraulic circuit of the construction machine which concerns on embodiment of this invention. It is explanatory drawing explaining an example of the direction control valve of the hydraulic circuit of the construction machine which concerns on embodiment of this invention. It is a schematic sectional drawing explaining an example of the cross section (AA cross section of Fig.3 (a)) of the direction control valve of the hydraulic circuit of the construction machine which concerns on embodiment of this invention. It is a junction circuit diagram explaining an example of the junction direction control valve of the hydraulic circuit of the construction machine according to the embodiment of the present invention. It is a hydraulic circuit diagram explaining the other example of the hydraulic circuit of a construction machine. It is explanatory drawing explaining the direction control valve of the other example of the hydraulic circuit of a construction machine. It is a schematic sectional drawing explaining an example of the cross section (BB cross section of Fig.7 (a)) of the other example of the direction control valve of a hydraulic circuit.

  Non-limiting exemplary embodiments of the present invention will be described with reference to the accompanying drawings. In the description of all attached drawings, the same or corresponding members or parts are denoted by the same or corresponding reference numerals, and redundant description is omitted. Also, the drawings are not intended to show the relative ratio between members or parts. Accordingly, specific dimensions can be determined by one skilled in the art in light of the following non-limiting embodiments.

  Hereinafter, the present invention will be described using the construction machine 100 including the hydraulic circuit 20 and the control device 30 according to the embodiment of the present invention. The present invention is a construction machine including a plurality of center bypass passages (center bypass lines) other than the present embodiment, and a part of pressure oil using a cut valve (bleed-off valve, flow control valve, etc.). Is returned to the tank (bleed-off control), and any oil that supplies (combines) the pressure oil supplied to one center bypass passage to the other center bypass passage can be used. Can also be used. Construction machines that can use the present invention include hydraulic excavators, crane cars, bulldozers, wheel loaders and dump trucks, pile driving machines, pile removers, water jets, mud drainage treatment equipment, grout mixers, depth machines. Includes foundation and drilling machines.

(Construction machine configuration)
A schematic configuration of a construction machine 100 in which the present invention can be used will be described with reference to FIG. Here, the construction machine is a machine that performs a desired operation using a hydraulic actuator in the present embodiment.

  As shown in FIG. 1, the construction machine 100 includes, as hydraulic actuators, a boom 11 whose base end is pivotally supported on the upper swing body 10Up, an arm 12 pivotally supported on the distal end of the boom 11, and a distal end of the arm 12. And a bucket 13 that is pivotally supported.

  The construction machine 100 extends and contracts the boom cylinder 11c in the longitudinal direction by supplying hydraulic oil (pressure oil) to the boom cylinder 11c of the boom 11. At this time, the boom 11 is driven in the vertical direction by expansion and contraction of the boom cylinder 11c. Further, the construction machine 100 is controlled by a boom direction control valve (for example, Vb1 and Vb2 in FIG. 2 described later) controlled in accordance with an operation amount (and an operation direction) of an operation lever of an operator (driver, operator). The hydraulic fluid supplied to the boom cylinder 11c is controlled. As a result, the construction machine 100 performs a desired operation according to the operation amount of the operation lever of the operator.

  Similarly to the case of the boom 11, the construction machine 100 drives the arm 12 and the bucket 13 by the expansion and contraction of the arm cylinder 12c and the bucket cylinder 13c. As in the case of the boom cylinder 11c, the construction machine 100 uses an arm direction control valve (for example, Va1 and Va2 in FIG. 2) and a bucket direction control valve (for example, Vbk in FIG. 2) to form an arm cylinder 12c and a bucket cylinder 13c. The hydraulic fluid supplied to the is controlled.

  Furthermore, the construction machine 100 uses the wheels and a turning device (for example, the lower traveling body 10Dw) to travel (moves back and forth and from side to side) and rotates (turns) the main body of the construction machine 100. The construction machine 100 uses, for example, a traveling direction control valve (for example, Vt1, Vt2, and Vst in FIG. 2) to run the construction machine 100 according to the amount of operation of the operation lever of the operator.

  A construction machine 100 that can use the present invention includes a hydraulic circuit (described later) 20 that supplies hydraulic oil (pressure oil) from a hydraulic pump to a hydraulic actuator, and a control device (described later) that controls the operation of each component of the construction machine 100. 30).

  Hereinafter, the hydraulic circuit 20 and the control device 30 of the construction machine 100 according to the embodiment of the present invention will be specifically described.

(Hydraulic circuit of construction machinery)
The hydraulic circuit 20 of the construction machine 100 according to the embodiment of the present invention will be described with reference to FIG. Here, the solid line described in FIG. 2 indicates an oil passage (pressure oil passage). In addition, a solid line added with // indicates an electric control system.

  The hydraulic circuit to which the present invention can be applied is not limited to that shown in FIG. That is, any hydraulic circuit having a plurality of center bypass passages and having a cut valve (bleed-off valve) disposed in the center bypass passage downstream of the plurality of directional control valves (direction control valve group). The present invention can also be applied to circuits. 2 includes two hydraulic pumps, the hydraulic circuit to which the present invention can be applied is not limited to one including two hydraulic pumps. That is, you may use this invention for a hydraulic circuit (construction machine) provided with three or more hydraulic pumps.

  As shown in FIG. 2, the hydraulic circuit 20 of the construction machine 100 according to the embodiment of the present invention includes two hydraulic pumps mechanically connected to an output shaft of a power source (a prime mover, an engine, a motor, etc.) not shown. P (first hydraulic pump P1 and second hydraulic pump P2) and two center bypass passages RC (first center bypass passage RC1) to which the pressure oil discharged from each of the two hydraulic pumps P is supplied And a second center bypass passage RC2), a directional control valve (such as the first traveling directional control valve Vt1) for controlling the hydraulic actuator (such as the boom 11 in FIG. 1), and a directional control valve for traveling straight (such as traveling). Direct valve) Vst. The hydraulic circuit 20 includes a bleed-off valve Vbo (a first bleed-off valve Vbo1 and a second bleed-off valve Vbo2) disposed downstream (for example, the most downstream) of the center bypass passage RC. Further, the hydraulic circuit 20 includes a merging circuit RJ that supplies the pressure oil supplied to one center bypass passage of the plurality of center bypass passages to another center bypass passage (hereinafter referred to as “merging”).

  In the hydraulic circuit 20 according to the present embodiment, a directional control valve (Vt1 or the like) is arranged in series with the center bypass passage RC, and a bleed-off valve Vbo is arranged downstream of the center bypass passage RC. Specifically, the hydraulic circuit 20 includes a first traveling direction control valve (for example, a left traveling direction control valve) Vt1 and a preliminary direction in a first center bypass passage RC1 corresponding to the first hydraulic pump P1. The control valve Vop, the turning direction control valve Vsw, the second boom direction control valve Vb2, the first arm direction control valve Va1, and the first bleed-off valve Vbo1 are arranged in series. In addition, the hydraulic circuit 20 includes a second traveling direction control valve (for example, a right traveling direction control valve) Vt2 and a bucket direction control valve Vbk in the second center bypass passage RC2 corresponding to the second hydraulic pump P2. The first boom direction control valve Vb1, the second arm direction control valve Va2, and the second bleed-off valve Vbo2 are arranged in series. Further, the hydraulic circuit 20 has a straight running valve Vst disposed upstream of the second center bypass passage RC2.

  That is, the hydraulic circuit 20 has a plurality of directional control valves arranged in series in the center bypass passage RC. Further, the hydraulic circuit 20 arranges the directional control valves in tandem by arranging a plurality of directional control valves in series in the two center bypass passages RC1, RC2. In the following description, a group composed of a plurality of directional control valves arranged in tandem in the center bypass passage RC is referred to as a “directional control valve group”.

  The hydraulic circuit 20 according to the present embodiment is a remote controller generated in accordance with operation information corresponding to the operation of the operator's operation lever (for example, information regarding the operation amount, information regarding the operation direction, hereinafter referred to as “operation information”). The pressure (secondary pressure of the remote control valve) is input to the direction control valve (Vt1 or the like) corresponding to the operated operation lever. At this time, the direction control valve switches the position of the spool in accordance with the remote control pressure introduced at both ends of the spool (flow rate control spool), and the flow rate (operation amount) and direction (operation direction) of the pressure oil (hydraulic oil) To control.

  Further, the hydraulic circuit 20 according to the present embodiment uses the bleed-off valve Vbo (for example, Vbo1) disposed downstream of the center bypass passage RC (for example, RC1), and the pressure oil discharged from the hydraulic pump P (for example, P1). Part (surplus) of the oil is returned to the hydraulic oil tank Tnk (bleed-off control is performed). Accordingly, the construction machine 100 can control the flow rate of the hydraulic oil (pressure oil) supplied to the hydraulic cylinder (for example, 11c), and can control the drive (operation) of the hydraulic actuator (for example, 11 in FIG. 1). .

  Here, in this embodiment, the bleed-off valve Vbo includes an unload position where the opening area is maximum and a block position where the opening area is zero. The bleed-off valve Vbo is switched from the unload position to the block position using the pressure oil of the pilot pump Pp controlled by the control device 30 described later, and its opening area is changed. Accordingly, the bleed-off valve Vbo can return (return) the pressure oil having a desired flow rate corresponding to the changed opening area to the hydraulic oil tank.

  The hydraulic circuit 20 of the construction machine 100 according to the embodiment of the present invention joins the pressure oil supplied to one center bypass passage to another center bypass passage using the joining circuit RJ. Here, in this embodiment, the merging circuit RJ, as shown in FIG. 2, is a merging direction control valve that controls the flow direction (hereinafter referred to as “inflow direction”) of the pressure oil supplied into the merging circuit RJ. Vj is provided. In this embodiment, the merging circuit RJ uses pressure oil generated by using the pilot pump Pp (the first pilot pump Pp1 and the second pilot pump Pp2) as a pilot port (control port) of the merging direction control valve Vj. ). Accordingly, the hydraulic circuit 20 (merging circuit RJ) controls the merging direction control valve Vj.

  Specifically, the merging circuit RJ according to the present embodiment uses the merging direction control valve Vj based on the operation information input by the operator using the operation lever to supply the pressure oil supplied to the center bypass passage RC1. It is possible to select (control) to join the center bypass passage RC2 or to join the pressure oil supplied to the center bypass passage RC2 to the center bypass passage RC1. That is, the hydraulic circuit 20 (joining circuit RJ) of the construction machine 100 according to the embodiment of the present invention can join the pressure oil in both directions of the center bypass passages RC1 and RC2.

  The details of the operation in which the hydraulic circuit 20 joins the pressure oil using the joining circuit RJ and the like will be described later (the operation to join the pressure oil). Moreover, the hydraulic circuit 20 (merging circuit RJ) of the construction machine 100 in which the present invention can be used may be configured to merge the pressure oil into only one of the center bypass passage RC1 or RC2, for example.

(Internal passage of direction control valve)
The internal passage RV of the directional control valve disposed in the hydraulic circuit 20 of the construction machine 100 according to the embodiment of the present invention will be described below.

  The hydraulic circuit 20 according to the present embodiment includes a directional control valve group (a plurality of directional control valves). Further, the directional control valve according to the present embodiment has, as the internal passage RV, a first internal passage that flows the supplied pressure oil to the center bypass passage RC, and a second that supplies the supplied pressure oil to the hydraulic actuator. And an internal passage. That is, the plurality of directional control valves constituting the directional control valve group are each provided with a first internal passage and a second internal passage.

  Furthermore, in the present embodiment, the opening of the first internal passage is not fully closed even when the spool position of the direction control valve is switched. That is, in the present embodiment, the first internal passage has substantially the same passage area regardless of the spool position of the direction control valve. The substantially same passage area means that the effective passage area through which the pressure oil actually passes does not change substantially compared to the increase / decrease amount of the passage area that changes due to the spool position displacement.

  Thereby, the hydraulic circuit 20 of the construction machine 100 according to the embodiment of the present invention can form a parallel passage by the center bypass passage RC and the first internal passage. Further, the hydraulic circuit 20 according to the present embodiment can form a parallel passage corresponding to the passage area of the first internal passage. Furthermore, the hydraulic circuit 20 according to the present embodiment can supply pressure oil to the directional control valve group (a plurality of directional control valves) only from the formed parallel passage.

  Note that the traveling direction control valves (for example, Vt1 and Vt2 in FIG. 2) among the plurality of direction control valves may have a configuration in which the opening of the first internal passage is fully closed (for example, RV1t in FIG. 2). Thereby, the construction machine 100 (the hydraulic circuit 20 thereof) can ensure traveling stability (flow rate of hydraulic oil necessary for traveling) during traveling.

  Further, the first internal passage (spool) of the directional control valve according to the present embodiment does not include a gap (hereinafter referred to as “bleed opening”) for returning the pressure oil to the hydraulic oil tank. Note that, as described above, the hydraulic circuit 20 according to the present embodiment can perform bleed-off control (unified bleed-off control) using the bleed-off valve Vbo disposed on the most downstream side of the center bypass passage RC. .

  The second internal passage according to the embodiment of the present invention is an internal passage (for example, RV2 in FIG. 2) for supplying pressure oil to a hydraulic cylinder (for example, the arm cylinder 12c in FIG. 2). The second internal passage supplies pressure oil discharged from the hydraulic pump P to a hydraulic cylinder (such as the arm cylinder 12c in FIG. 2). When the spool position of the directional control valve is switched by the input remote control pressure, the second internal passage according to the present embodiment changes the path of the internal passage and supplies the hydraulic oil (hydraulic oil) supplied to the hydraulic cylinder. ) Is changed in flow rate (operation amount) and direction (operation direction). Thereby, the direction control valve (construction machine 100) can control the operation of the hydraulic cylinder (hydraulic actuator).

  An example of the internal passage RV (spool shape) of the directional control valve disposed in the hydraulic circuit 20 of the construction machine 100 according to the embodiment of the present invention will be specifically described with reference to FIG. In addition, the direction control valve (spool shape etc.) which can be used for this invention is not limited to what is shown in FIG.

  As shown in FIG. 3A, the directional control valve V of the hydraulic circuit 20 according to the embodiment of the present invention is supplied from the inlet port PIprt supplied with pressure oil via the center bypass passage RC and the inlet port PIprt. Outlet port POprt for flowing the pressurized oil into the center bypass passage RC, cylinder port Cprt for supplying the pressure oil supplied to the directional control valve V to the hydraulic cylinder, and hydraulic oil discharged from the hydraulic cylinder for the hydraulic oil tank And a tank port Tprt for discharging to the tank. In the hydraulic circuit 20 according to the present embodiment, a check valve Vch is disposed at the inlet of the second internal passage RV2 to which pressure oil is supplied.

  As shown in FIG. 3B, the directional control valve V according to the present embodiment reverses the pressure oil (working oil) Oc supplied from the center bypass passage RC when the spool is displaced (for example, Mb in the figure). The oil is supplied from the cylinder port CprtB to the hydraulic cylinder (for example, 11c in FIGS. 1 and 2) through the stop valve Vch and the second internal passage RV2. At this time, the pressure oil (hydraulic oil) Ot discharged from the hydraulic cylinder to the cylinder port CprtA is discharged from the tank port Tprt to the hydraulic oil tank.

  Further, as shown in FIG. 3C, the directional control valve V according to the present embodiment is configured so that the pressure oil (operating oil) Oc supplied from the center bypass passage RC when the spool is displaced (for example, Mc in the figure). Is supplied from the cylinder port CprtB to the hydraulic cylinder (for example, 11c in FIGS. 1 and 2) via the check valve Vch and the second internal passage RV2. At this time, the pressure oil (hydraulic oil) Ot discharged from the hydraulic cylinder to the cylinder port CprtA is discharged from the tank port Tprt to the hydraulic oil tank.

  As shown in FIG. 3, the hydraulic circuit 20 of the construction machine 100 according to the embodiment of the present invention does not perform bleed-off control in the directional control valve V (because the directional control valve V does not have a bleed opening). The opening area of the first internal passage RV1 of the valve V can be increased. As a result, the direction control valve V according to the present embodiment can increase the opening area of the first internal passage RV1 of the direction control valve V, thereby reducing the pressure loss of the pressure oil passing through the center bypass passage RC. can do.

  In addition, the hydraulic circuit 20 of the construction machine 100 according to the present embodiment arranges a plurality of directional control valves V in series with the center bypass passage RC, whereby the center bypass passage RC and the plurality of first internal passages RV1 (directions). The passage formed by the control valve V) can function as a parallel passage. For this reason, the hydraulic circuit 20 according to the present embodiment does not require a separate parallel passage, and can reduce the size of the direction control valve V (reducing the size of the spool in the axial direction and the radial direction). The hydraulic circuit 20 according to the present embodiment can reduce the size of the bridge passage Rb (FIG. 3A), for example.

  The hydraulic circuit 20 of the construction machine 100 according to the embodiment of the present invention uses the plurality of directional control valve groups V to flow the pressure oil into the center bypass passage RC. That is, the hydraulic circuit 20 of the construction machine 100 according to the embodiment of the present invention flows the pressure oil into the center bypass passage RC (parallel passage) using the direction control valve group Gv.

  Specifically, as shown in FIG. 4, the hydraulic circuit 20 in which the directional control valve group Gv (a plurality of directional control valves V) is arranged has the same passage area regardless of the spool position of the directional control valve. A parallel passage can be formed by one internal passage and the center bypass passage RC. Here, the hydraulic circuit 20 flows out the pressure oil Op supplied from the inlet port PIprt to the outlet port POprt via the first internal passage RV1 of the direction control valve V, and flows out to the center bypass passage RC. The hydraulic circuit 20 performs bleed-off control (unified bleed-off control) using a bleed-off valve Vbo disposed on the most downstream side of the center bypass passage RC.

  As a result, the hydraulic circuit 20 of the construction machine 100 according to the embodiment of the present invention does not need to provide a plurality of bleed openings in the spools of the plurality of directional control valves V (directional control valve group Gv). The shape of RC can be simplified. Moreover, since the hydraulic circuit 20 according to the present embodiment can reduce the bent portion of the center bypass passage RC, the pressure loss of the pressure oil passing through the center bypass passage RC can be reduced.

  Further, the hydraulic circuit 20 of the construction machine 100 according to the embodiment of the present invention causes the passage formed by the center bypass passage RC and the first internal passage RV1 to function as a parallel passage, and the center bypass passage RC ( Since the pressure loss of the pressure oil passing through the center bypass passage RC can be reduced by simplifying the shape of the parallel passage), the pressure oil joined by the joining circuit RJ is supplied to a desired directional control valve. The center bypass passage RC (parallel passage) can be used as the passage.

(Operation to join pressure oil)
The hydraulic circuit 20 of the construction machine 100 according to the embodiment of the present invention uses the junction circuit RJ and the bleed-off valve Vbo (FIG. 2) to supply the pressure oil supplied to one center bypass passage to another center bypass passage. Merge. Here, the junction circuit RJ according to the present embodiment includes a junction direction control valve Vj. Further, the junction circuit RJ according to the present embodiment further includes a check valve Vjc corresponding to the spool position (inflow direction) of the junction direction control valve Vj.

  The junction circuit RJ that can be used in the present invention is not limited to the junction circuit arranged on the upstream side of the bleed-off valve Vbo shown in FIG. That is, the merging circuit RJ that can be used in the present invention has an arbitrary position of the center bypass passage RC in the gap between the hydraulic pump P and the bleed-off valve Vbo (cut valve) (an arbitrary directional control valve of the directional control valve group). (Upstream side or downstream side).

  The junction circuit RJ that can be used in the present invention includes, for example, a center bypass passage RC1 immediately upstream of the preliminary directional control valve Vop and a upstream side of the bucket directional control valve Vbk as shown in FIG. Between the center bypass passage RC2 or the center bypass passage RC1 immediately downstream of the auxiliary directional control valve Vop and the center bypass passage immediately downstream of the bucket directional control valve Vbk as shown in FIG. 5C. A junction circuit RJ may be arranged between RC2. At this time, if the merging circuit RJ is a hydraulic circuit as shown in FIG. 2, the positions of the auxiliary direction control valve Vop and the turning direction control valve Vsw are switched, and the auxiliary direction control valve Vop and the bucket direction control are switched. The positional relationship may be such that the valve Vbk is adjacent.

  The merging circuit RJ according to the present embodiment controls the inflow direction of the pressure oil in the merging circuit RJ by changing the position of the spool of the merging direction control valve Vj. The merging circuit RJ inputs the pressure oil generated by using the pilot pump Pp (FIG. 2) to the pilot port (control port) of the merging direction control valve Vj, thereby setting the spool position of the merging direction control valve Vj. Control. Further, the merging circuit RJ supplies the pressure oil to the other center bypass passage (merges) using the pressure of the pressure oil in the one center bypass passage that has been raised by reducing the opening area of the bleed-off valve Vbo. ).

  Specifically, as shown in FIG. 5A, the junction circuit RJ according to the present embodiment is a pilot pressure generated based on the operation information input to the construction machine 100 (discharge pressure of the pilot pump Pp). A and B are respectively input to the control ports of the merging direction control valve Vj. At this time, the merging direction control valve Vj displaces the position of the spool (for example, to the position PA or position PB in the figure) according to the pilot pressures A and B and the negative forces of the springs Spra and Sprb. Thereby, the merging direction control valve Vj controls the inflow direction of the pressure oil in the merging circuit RJ. Further, the junction circuit RJ according to the present embodiment uses the check valve Vjc to prevent the flow of pressure oil in the reverse direction with respect to the inflow direction.

  The junction circuit RJ reduces the pressure area of the bleed-off valve Vbo1 to reduce the pressure oil pressure in the center bypass passage RC1, for example, in order to join the pressure oil supplied to the center bypass passage RC1 to the center bypass passage RC2. It is possible to raise and to displace (Ra) the spool of the merging direction control valve Vj to the position PA. In addition, the junction circuit RJ reduces the opening area of the bleed-off valve Vbo2 by, for example, reducing the opening area of the bleed-off valve Vbo2 in order to join the pressure oil supplied to the center bypass passage RC2 to the center bypass passage RC1. The pressure can be increased and the spool of the merging direction control valve Vj can be displaced (Rb) to the position PB.

  Note that the method of switching the spool position of the merging direction control valve Vj is not limited to the above direction (pressurizing method). The merging direction control valve Vj may be, for example, a solenoid valve (ON / OFF switching) or a combination of other (hydraulic pilot) mechanical mechanisms. Further, the position of the spool of the merging direction control valve Vj is not limited to the above positions (position PA and position PB). The merging direction control valve Vj may be configured to eliminate the merging shock by switching proportionally regardless of the lever operation amount, for example. Furthermore, the check valve Vjc may be configured not to be built in the merging direction control valve Vj.

(Control device for construction machinery)
In this embodiment, the controller 30 of the construction machine 100 uses a controller 30C (FIG. 2) that is mounted to control the operation of the entire construction machine 100. Here, the controller 30 </ b> C (control device 30) is a device that instructs each component of the construction machine 100 to operate and controls the operation of each component. The controller 30C (control device 30) can be configured by an arithmetic processing device including a CPU (Central Processing Unit) and a memory (ROM, RAM, etc.).

  As shown in FIG. 2, in this embodiment, the controller 30C controls the operation of the regulator R (R1, R2) based on the operation information (operation amount of the operation lever, operation direction, etc.) input to the construction machine 100. Control. Thus, the discharge amount of the hydraulic pump P (P1, P2) is controlled by the regulator R.

  Further, the controller 30C generates remote control pressure using a remote control valve or the like based on operation information input to the construction machine 100. Next, the controller 30C inputs the generated remote control pressure to the direction control valve (Vt1 or the like) using a remote control circuit (not shown). Thus, the direction control valve can switch the spool position and control the hydraulic oil supplied to the hydraulic actuator by using the input remote control pressure.

  Furthermore, in the embodiment of the present invention, the controller 30C controls the merging direction control valve Vj and the bleed-off valve Vbo based on information input to the construction machine 100. The controller 30C controls the discharge pressure of the pilot pump Pp that is input to the merging direction control valve Vj and the bleed-off valve Vbo, for example, according to a predetermined specific operation situation. The position and the opening degree (opening area) of the bleed-off valve Vbo are controlled. Thereby, the controller 30C can control the inflow direction of the junction circuit RJ and the pressure of the pressure oil flowing in.

  The control of the controller 30C is exemplified below.

  (1) The controller 30C (control device 30), for example, at the time of preliminary priority, a center bypass passage (for example, a preliminary directional control valve Vop in FIG. 2) corresponding to a hydraulic actuator that prioritizes operation is disposed (for example, The pressure oil supplied to another center bypass passage (for example, RC2 in FIG. 2) can be joined to RC1) in FIG. Thus, the controller 30C can prioritize the operation of the spare hydraulic actuator.

  (2) The controller 30C (control device 30) has a center bypass passage in which a directional control valve (Vbk in FIG. 2) corresponding to a hydraulic actuator (for example, the bucket 13 in FIG. 1) that gives priority to the operation is combined, for example, during a combined operation. The pressure oil supplied to the other center bypass passage (RC1 in FIG. 2) can be joined to (RC2 in FIG. 2). Thereby, the controller 30C can give priority to the operation of the arbitrary hydraulic actuator (bucket 13) (increase the operation speed).

  As described above, according to the hydraulic circuit 20 of the construction machine 100 or the control device 30 thereof according to the embodiment of the present invention, the bleed-off control is not performed by the directional control valve, and the first internal passage of the directional control valve is used. Since the pressure oil discharged from the hydraulic pump P can be supplied downstream of the center bypass passage RC, the pressure loss of the pressure oil passing through the center bypass passage RC can be reduced. Further, according to the hydraulic circuit 20 of the construction machine 100 or the control device 30 thereof according to the embodiment of the present invention, the output port and the center bypass passage on the upstream side of the cut valve (bleed-off valve) when the junction circuit is formed. There is no need to provide an input port and an external passage that connects the output port and the input port on the side that joins the RC, so that the hydraulic circuit can be reduced in size and can be easily manufactured. Furthermore, according to the hydraulic circuit 20 or the control device 30 of the construction machine 100 according to the embodiment of the present invention, the inflow direction of the pressure oil in the merging circuit RJ is controlled using the merging direction control valve Vj and the bleed-off valve Vbo. Therefore, the pressure oil can be merged in both directions in the plurality of center bypass passages RC.

  Further, according to the hydraulic circuit 20 of the construction machine 100 or the control device 30 thereof according to the embodiment of the present invention, the bleed-off control is performed by the directional control valve using the bleed-off valve Vbo disposed downstream of the center bypass passage RC. Without the bleed opening in each directional control valve, the bleed-off control can be performed downstream of the center bypass passage RC. Thereby, according to the hydraulic circuit 20 or the control device 30 thereof according to the present embodiment, the internal passage (for example, the first internal passage) of the directional control valve is compared with the case where the bleed-off control is performed by the plurality of directional control valves. ), The pressure loss of the pressure oil passing through the center bypass passage RC can be reduced. Further, according to the hydraulic circuit 20 of the construction machine 100 or the control device 30 thereof according to the embodiment of the present invention, since the directional control valve is not provided with the bleed opening, the size of the directional control valve in the longitudinal direction can be reduced. it can. Thereby, according to the hydraulic circuit 20 or the control device 30 thereof according to the present embodiment, the direction control valve can be reduced in size compared to the case where the direction control valve is provided with a bleed opening, and the manufacture thereof is facilitated. can do.

  Furthermore, according to the hydraulic circuit 20 of the construction machine 100 or the control device 30 thereof according to the embodiment of the present invention, the plurality of directional control valves V are arranged in series in the center bypass passage RC, so that A passage formed by one internal passage RV1 (direction control valve V) can function as a parallel passage. Further, according to the hydraulic circuit 20 or the control device 30 thereof according to the present embodiment, the passage formed by the center bypass passage RC and the plurality of first internal passages RV1 can function as a parallel passage. There is no need to provide a separate passage, and the direction control valve V can be reduced in size. Furthermore, according to the hydraulic circuit 20 or the control device 30 according to the present embodiment, the bleed-off valve Vbo can be functioned as a cut valve (neutral cut valve) for the junction circuit RJ. There is no need to prepare. Thereby, the hydraulic circuit 20 of the construction machine 100 or the control device 30 thereof according to the embodiment of the present invention has advantageous effects for downsizing, facilitating manufacture, and cost reduction of the construction machine 100 as a whole.

  FIG. 6 shows another example of the hydraulic circuit of the construction machine. In the hydraulic circuit of FIG. 6, bleed openings (for example, Sbo of FIG. 7) can be provided in the spools of the directional control valves (Va <b> 1, etc. of FIG. 6) in order to perform bleed-off control. That is, the construction machine including the hydraulic circuit of FIG. 6 can perform bleed-off control by changing the opening area of the bleed opening.

  Here, in the construction machine provided with the hydraulic circuit of FIG. 6, since the bleed openings are respectively provided in the spools of the direction control valve, the center bypass passage (in FIG. 4) is compared with the case of the hydraulic circuit according to the present invention (FIG. 4). The pressure loss of the pressure oil passing through RCm) in FIG. 8 may increase.

  Further, in the hydraulic circuit of FIG. 6, in order to form a merging circuit, the cut valve Vct and the output port Pout are provided to flow out the pressure oil, and the input port Pin is further provided to flow in (merge) the pressure oil. For this reason, the passage of the hydraulic circuit (for example, the passage connecting the output port Pout and the input port Pin) becomes complicated, and the pressure loss of the pressure oil may increase. Further, in the hydraulic circuit of FIG. 6, it is necessary to provide another set of cut valve Vct, output port Pout, and the like in order to allow the pressure oil to merge in both directions. That is, due to the cut valve Vct, the output port Pout, and the like, in the case of FIG. 6, the hydraulic circuit may be enlarged as compared with the hydraulic circuit according to the present invention (FIG. 4).

  As mentioned above, although preferable embodiment of this invention containing the hydraulic circuit of a construction machine or its control apparatus was described, this invention is not restrict | limited to embodiment mentioned above. The present invention can be variously modified or changed in light of the appended claims.

DESCRIPTION OF SYMBOLS 100: Construction machine 11: Boom 11c: Boom cylinder 12: Arm 12c: Arm cylinder 13: Bucket 13c: Bucket cylinder 20: Hydraulic circuit 30: Control means 30C: Controller Gv: Direction control valve group V: Direction control valve (control valve) )
Va1, Va2, Vb1, Vb2, Vbk, Vsw, Vop, Vt1, Vt2: Directional control valve for hydraulic actuator Vst: Directional control valve for straight travel (straight travel valve)
Vbo: Bleed-off valve (cut valve)
Vch, Vjc: Check valve Vj: Merge direction control valve (switching valve, proportional switching valve, etc.)
RJ, RJa, RJb: Junction circuit RC, RC1, RC2: Center bypass passage (center bypass line)
RV1: first internal passage (bleed-off internal passage, PT opening internal passage)
RV2: Second internal passage (internal passage for cylinder port)
PIprt: Inlet port POprt: Outlet port Tprt: Tank port Cprt, CprtA, CprtB: Cylinder port P, P1, P2: Hydraulic pump R, R1, R2: Regulator Tnk: Hydraulic oil tank (tank)
Pp, Pp1, Pp2: Pilot pump

The present invention relates to a shovel and a directional control valve group for construction machinery.

A directional control valve group for a construction machine according to an embodiment of the present invention is a directional control valve group for a construction machine that controls a supply amount of pressure oil discharged from a hydraulic pump to a hydraulic actuator. A cylinder port that supplies pressure oil, a bridge passage that is connected / disconnected by a change in position of the cylinder port and the spool, and an internal passage that supplies pressure oil discharged from the hydraulic pump to the bridge passage , it is Bei Ete and a check valve for preventing the pressure oil return to the internal passage.

100: Construction Machinery 11: Boom 11c: boom cylinder 12: Arm 12c: arm cylinder 13: bucket 13c: bucket cylinder 20: Hydraulic circuit 30: Control device 30C: Controller Gv: directional control valve Group V: directional control valve (control valve )
Va1, Va2, Vb1, Vb2, Vbk, Vsw, Vop, Vt1, Vt2: Directional control valve for hydraulic actuator Vst: Directional control valve for straight travel (straight travel valve)
Vbo: Bleed-off valve (cut valve)
Vch, Vjc: Check valve Vj: Merge direction control valve (switching valve, proportional switching valve, etc.)
RJ, RJa, RJb: Junction circuit RC, RC1, RC2: Center bypass passage (center bypass line)
RV1: first internal passage (bleed-off internal passage, PT opening internal passage)
RV2: Second internal passage (internal passage for cylinder port)
PIprt: Inlet port POprt: Outlet port Tprt: Tank port Cprt, CprtA, CprtB: Cylinder port P, P1, P2: Hydraulic pump R, R1, R2: Regulator Tnk: Hydraulic oil tank (tank)
Pp, Pp1, Pp2: Pilot pump

Claims (11)

A directional control valve group for a construction machine that controls a supply amount of hydraulic oil discharged from a hydraulic pump to a hydraulic actuator,
A cylinder port for supplying pressure oil to the hydraulic actuator;
A bridge passage connected in communication / non-communication by a change in position of the cylinder port and the spool;
An internal passage for supplying pressure oil discharged from the hydraulic pump to the bridge passage,
The spool is disposed in the internal passage;
Directional control valve group for construction machinery. The internal passage has substantially the same passage area regardless of the position of the spool.
The directional control valve group for construction machines according to claim 1. A second spool arranged in tandem upstream or downstream of the spool in the internal passage;
The directional control valve group for construction machines according to claim 1 or 2. The internal passage communicates with the second spool in a state where the internal passage communicates with a change in the position of the cylinder port and the spool.
The directional control valve group for construction machines according to claim 3. In addition, a bleed-off valve is provided,
The bleed-off valve performs bleed-off control of pressure oil supplied through the internal passage by changing an opening area of the bleed-off valve.
The directional control valve group for construction machines according to any one of claims 1 to 3. The bleed-off valve is disposed between the internal passage and the tank;
The directional control valve group for construction machines according to claim 5. The opening area of the bleed-off valve and the spool changes according to operation information input to the construction machine.
The directional control valve group for construction machines according to claim 5 or 6. Two cylinder ports are formed and formed on both sides of the internal passage,
The directional control valve group for construction machines according to any one of claims 1 to 7. When one of the two cylinder ports is in communication with the internal passage, the other is in non-communication.
The directional control valve group for construction machines according to claim 8. A tank port is formed outside each of the cylinder ports, and the cylinder port is connected to the tank port in communication / non-communication.
The directional control valve group for construction machines according to any one of claims 4 to 9. According to the position of the spool, the flow rate of pressure oil supplied from the internal passage to the cylinder port is controlled.
The directional control valve group for construction machines according to any one of claims 1 to 10.

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